Watercare's Sven Harlos says it will need more funding if it gets the green light to take an additional 150 million litres of water from the Waikato River.
If Watercare gets the green light to take an additional 150 million litres a day from the Waikato River it will need $160 million for a new permanent water treatment plant at Tuakau.
That's the message from the council controlled organisation which has been at the frontline of the city's drought recovery.
Watercare is currently putting the finishing touches on a new $145 million temporary water treatment plant in Tuakau, which will provide Auckland with an extra 50 million litres a day from the Waikato River.
The new facility is expected to go live in June. It was included in a $224 million package approved by the Auckland Council last year to boost the city's water supply as part of its drought recovery response.
The current works include work on a temporary treatment plant, a pipeline from the river to the facility and a new pumping station. The scheme is the largest single drought recovery project.
According to Watercare infrastructure projects manager Sven Harlos, design work on the project started in May last year and construction got underway in October.
"To build something like this in a year's time isn't an easy undertaking," he said.
Harlos said there are still a lot of steps it will have to go through, including testing, before it can start supplying water to the city.
"There's a much higher level of water treatment required than with the water taken from the city's dams," he said.
But Harlos was confident everything was on budget and on schedule.
However, he said if Watercare gets approval to take an additional 150 million litres per day from the Waikato River, on top of the 175 million litres a day it currently takes, more funding will be needed for a permanent plant on the same site.
He said while it will be able to use 80 per cent of the equipment from its existing facilities, it will still need a further $160 million in funding for the necessary works.
Harlos said this would include new intakes and pipelines and a new state of the art treatment plant.
"As soon as the consent is approved we will start on the design work."
The existing Waikato Water Treatment Plant usually provides up to 30 per cent of the drinking water for the Auckland region.
Last year Watercare applied to the Waikato Regional Council to extract an additional 150 million litres per day from the Waikato River and the resource consent is currently before a Board of Inquiry.
But the application has been the subject of strong criticism from the Hamilton City Council which was expected to vote on Thursday on a submission opposing its bid to take more water from the Waikato River.
The council's draft submission said staff had "serious concerns" about how Watercare's application might affect Hamilton's ability to secure enough water for its growing population.
Hamilton's population is projected to increase from 176,000 to about 200,000 people by 2030.
Auckland Mayor Phil Goff publicly criticised Watercare last year for its last minute request for $224 million to fund key projects to boost the city's water supply in response to the drought.
At the time the council was finalising its emergency budget and was expecting to see its revenue drop by $500 million due to Covid-19.